Genes Linked to 'Pot' Belly

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THURSDAY, Nov. 5, 2009 (HealthDay News) -- New research sheds light on the possible link between the genes you inherit and the size of your belly.

Participants in a French study doubled their risk of having fat around the abdomen if they had a certain genetic trait, and the more of these traits one had, the greater the risk for a pot belly.

The study was looking at metabolic syndrome, a condition in which abdominal obesity, high cholesterol and high blood pressure combine to raise the risk of several diseases such as stroke, heart disease and type 2 diabetes.

The findings are just one more piece of the obesity puzzle, a nutrition specialist said.

"Certainly it adds to the body of knowledge, but we need to look at what it means within the big picture and context of all the other obesity research," said Lona Sandon, an assistant professor at University of Texas Southwestern Medical Center and spokeswoman for the American Dietetic Association.

Results of the study, which was designed to explore a possible link between genes and metabolic syndrome, are published in the November issue of the Journal of Nutrition.

The researchers followed 1,754 French people for seven and a half years, tracking what they ate. They found that having any one of five genetic traits doubled the risk that a person would have abdominal obesity, and that eating a lot of saturated fats boosted the risk even more. But they also found that having one of the genetic traits didn't boost the risk of metabolic syndrome.

Sandon said the study doesn't confirm that the genetic trait directly leads to obesity. The findings, she said, show "an association, not a cause-and-effect."

Also, she pointed out that while the study found a relationship between the gene and abdominal obesity, some subjects were consuming more than 15.5 percent of their calories from saturated fat.

The current recommendation is 10 percent for most healthy people and 7 percent for those with high cholesterol and other metabolic risk factors for heart disease, she said.

In the larger picture, researchers are beginning to understand how genetics are connected to obesity and "how those genes are affected by environment and food components," Sandon said.

"The mystery is how do we put this into real health recommendations, and how do multiple genes work together to promote or squelch obesity," she said. "If there were just one gene related to obesity, the answer might be simple. But we know multiple genes are involved, so it is difficult to make hard and fast conclusions about what people should do with this information."

When it comes to obesity, the factors of genetics, diet and exercise -- or lack thereof -- are indeed "highly entangled," said study co-author Dr. Richard Planells, a professor of biochemistry at University of Aix-Marseille II in France.

What to do? At the moment, genetic tests to track these particular genes aren't feasible. "Many other genes have to be analyzed before one can design a genetic map," Planells explained.

Even if there was such a test, "the majority of control is always in your hands," added Cynthia Sass, a registered dietitian and author in New York City. "Even if you have strong genetic predispositions to obesity or any disease, you are not guaranteed to develop that disease. Given the exact same lifestyle, yes, you will have a higher risk, but the bottom line is that the majority of the risk lies in how you treat your body, and that's empowering."